Pipe clamping device

ABSTRACT

A pipe-clamping device for positioning two pipe sections in correct axial alignment and with a desired axial end separation therebetween comprises two sets of pipe-clamping shoes which are moved into positive clamping engagement with first and second pipe sections respectively by chains engaging those shoes and extending around respective ones of the pipe sections, the shoes being provided with slotted plates for receiving selected links of the chains and terminal turnbuckle adjusting mechanisms on the chains being used to tighten them and to provide the positive clamping engagement. Radially disposed and adjustable pipepositioning or centering pins are provided on extensions of the first set of shoes for obtaining correct axial alignment of the second pipe section with the first pipe section. Removable turnbuckle mechanisms extend between the pipe-clamping shoes of one set and those of the other set to permit adjustment of the axial separation between the two pipe sections.

United States Patent 91 I Arntz et al.

[ 1 3,722,038 [451 Mar. 27, 1973 Oakridge Drive, York, Pa. 17402;

Geuriiey Elden Walton, 322 Reinecke Drive, York, Pa. 17403 [22] Filed: Feb. 9, 1972 21 Appl. No.: 226,563

[52] US. Cl ..24/81 PE, 219/161, 269/43, 285/287 [51] Int. Cl. ....'...A44b 21/00, 1325b 1/20, F161 13/02 [58] Field of Search ..285/2l 286, 287; 24/73 R, 24/81 R, 279, 81 PE; 269/43; 219/161 Parr ..24/81 PE X Primary Examiner-Donald A. Griffin Attorney-J-lenry N. Paul, Jr. et al.

[5 7] ABSTRACT A pipe-clamping device for positioning two pipe sections in correct axial alignment and with a desired,

axial end separation therebetween comprises two sets of pipe-clamping shoes which are moved into positive clamping engagement with first and second pipe sec-- tions respectively by chains engaging those shoes and extending around respective ones of the pipe sections, the shoes being provided with slotted plates for receiving selected links of the chains and terminal turnbuckle adjusting mechanisms on the chains being used to tighten them and to provide the positive clamping engagement. Radially disposed and adjustable pipepositioning or centering pins are provided on extensions of the first set of shoes for obtaining correct axial alignment of the second pipe section with the first pipe section. Removable turnbuckle mechanisms extend between the pipe-clamping shoes of one set and those of the other set to permit adjustment of the axial separation between the two pipe sections.

35 Claims, 9 Drawing Figures SHEET 1 [IF 4 PATENTEUHARZ? I575 PATENTEUHARZY 1m SHEU 3 [IF 4 PATENTEUmzmn 7 2,03

SHEET 0F 4 WIIIII.

' FIG. 7 20 PIPE CLAMPING DEVICE BACKGROUND OF THE INVENTION The present invention relates to a pipe-clamping device and more particularly to a device intended for use in the positioning of two pipe sections to allow such pipe sections to be welded together.

Many of the clamping devices presently used for positioning and holding individual sections of pipeline in required relative positions for a welding operation are complex and expensive. The use of others of the clamping devices heretofore known for such a purpose is time-consuming and consequently increases the cost of the installation of a pipeline.

Other known clamping devices for the aforesaid purpose present the disadvantage that they can be used with pipe of only one diameter.

It is a principal object of this invention to provide a clamping device for the aforesaid purpose and which device is not only exceedingly simple in its construction but by the use of which two pipeline sections can be correctly aligned and positioned relatively rapidly thereby reducing the installed cost of a pipeline.

Yet another object of this invention is to provide a clamping device which permits the simple positioning of two pipeline sections in both the transverse and axial directions.

A further object of this invention is to provide a clamping device which in use is disposed totally outside the pipe sections being welded and which does not, therefore, require the use of lengthy control cables, hoses or mechanisms extending through one of the pipe sections as is the case with the known internal clamping devices.

One further object of this invention is to provide a pipe-clamping device which is easily removed from a pipeline after a welding operation of two pipe sections has been completed.

Another object of this invention is to provide a clamping device which can be used on pipe sections of different diameters.

' Other objects of the invention will become apparent as the description herein proceeds.

SUMMARY OF THE INVENTION Broadly the present invention provides a pipe-clamping device for holding adjacent first ends of a pair of pipe sections in desired mutual axial alignment and in desired axial end separation for a pipe-welding operation and which device comprises: a first set of at least three pipe-clamping shoes; a first set of flexible linkages for interconnecting said pipe-clamping shoes of said first set thereof; a first tightening means associated with said first set of flexible linkages whereby, when said pipe-clamping shoes of said first set thereof are disposed externally about a first one of such a pair of pipe sections in proximity to the first end of such a pipe section and in mutually angularly spaced apart positions thereabout, such flexible linkages can be tightened to move those pipe-clamping shoes into clamping engagement with such a first pipe section; at least three arms extending axially from three respective ones of said pipe-clamping shoes at radially outwardly disposed positions thereon; at least three pipe-positioning members extending generally radially inwardly from respective ones of said arms and adjustably mounted on those arms for positional adjustrnent'in generally radial directions whereby, when said first set of pipe-clamping shoes are disposed externally about the first one of the pipe sections in clamping engagement with that first pipe section, said pipe-positioning members can be radially adjusted to engage a second one of the pair of pipe sections in turn transversely to position that second one of the pair of pipe sections; a second set of at least three pipe-clamping shoes; a second set of flexible linkages for interconnecting said pipe-clamping shoes of said second set thereof; a second tightening means associated with said second set of flexible linkages whereby, when said pipe-clamping shoes of said second set thereof are disposed externally about the second one of the pair of pipe sections in proximity to the first end of that second pipe section and in mutually angularly spaced apart positions thereabout, said flexible linkages of said second set thereof can be tightened to move said pipe-clampingshoes of said second set thereof into clamping engagement with said second one of said pipe sections; and at least three axial adjustment members extending Other features of a pipe-clamping device in ac-' cordance with this invention will become apparent as the description herein proceeds as will the advantages obtained by the use of such a pipe-clamping device.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described merely by way of illustration with reference to the drawings in which:

FIG. 1 is a perspective and partly exploded view of one embodiment of a pipe-clamping device according to this invention and showing that device in use for clamping two pipe sections in a desired mutual position with certain parts being omitted for the sake of clarity;

FIG. 2 is a perspective view on an enlarged scale of one of the pipe-clamping shoes of a first set of such shoes of the pipe-clamping device shown in FIG. 1;

FIG. 3 is a fragmentary sectional view through the pipe-clamping shoe of FIG. 2 when taken as indicated by the arrows 3-3 of that figure;

FIG. 4 is a transverse sectional view through the pipe-clamping shoe of FIG. 2 when taken as indicated by the arrows 4-4 of that figure;

FIG. 5 is a transverse sectional view through another one of the pipe-clamping shoes of the first set of such shoes of the device shown in FIG. 1 when taken as in dicated by the arrows 5-5 of that figure;

FIG. 6 is a fragmentary sectional view through the pipe-clamping shoe of FIG. 5 when taken as indicated by the arrows 6-6 of that figure;

FIG. 7 is a fragmentary, longitudinal axial sectional view through the clamping device of FIG. 1 when taken as indicated by the arrows 7-7 of that figure but showing the two pipe sections finally aligned for a welding operation;

FIG. 8 is an enlarged fragmentary section when taken as indicated by the arrows 8-8 in FIG. 7; and

FIG. 9 is a perspective view similar to that of FIG. 2 but showing one of the pipe-clamping shoes of the second set of such shoes of the device shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The pipe-clamping device 10 includes a first set of three pipe-clamping shoes 13, 14 and 15 which, in use, are disposed in mutually angularly spaced apart positions about the pipe section 11 in proximity to a first end 16 thereof. The shoes 13 and 15 are also shown in FIGS. 2 and 4, and 5 respectively. The device 10 also includes a second set of three pipe-clamping shoes which are similarly disposed in mutually angularly spaced positions about the pipe section 12in proximity to a first end thereof, such pipe-clamping shoes being indicated at 17, 18 and 19 in FIG. 1 and the shoe 17 being shown on an enlarged scale in FIG. 9.

Referring further to the first set of pipe-clamping shoes 13, 14 and 15, it can now be noted that the shoes 13 and 14 are essentially identical to each other while the shoe 15 is constructed in a slightly different manner. The construction of the shoes 13 and 14 will now be described in greater detail with particular reference to FIGS. 2 to 4 from which it will be seen that the shoe 13 illustrated therein includes first and second generally cylindrical solid members 21 and 22 respectively which are disposed generally parallel to each other and which are interconnected, for example, by welding as at 23 to a third generally cylindrical and parallel solid member 24 which is disposed between the members 21 and 22 and which is positioned radially outwardly relative thereto when the pipe-clamping shoe 13 comprising such members is disposed in position on a pipe section such as the pipe secton 11. Fourth and fifth generally cylindrical solid members 25 and 26 respectively are secured, for example, by welding as at 27, to the members 21 and 22 respectively outwardly thereof. A sixth generally cylindrical solid member 28 is secured, for example, by welding as at 29, to the member 24 radially outwardly thereof. In use, each of the pipe-clamping shoes 13, 14 and 15 is disposed on the pipe section 11 in proximity to the first end 16 thereof so as to be essentially parallel to the axis of that pipe section 11 and with the cylindrical members 21 and 22 thereof peripherally engaging the pipe section 11.

It will further be noted that each of the pipe-clamping shoes 13 and 14 includes two plates 30 and 31 which extend outwardly from the shoes, the plate 30 being welded as at 32 to the generally cylindrical member 25 and the plate 31 being welded as at 33 to the generally cylindrical member 26. Each of the plates 30 and 31 is formed with an outwardly openended slot 34 as well as with an inturned outer edge flange or lip 35 through which a respective one of the aforementioned slots 34 also extends.

The pipe-clamping shoe 15 differs from the pipeclamping shoes 13 and 14 in that only one such slotted plate, namely plate 30, is provided on that shoe and in that, instead of the slotted plate 31, a shaft 36 is supported by axially spaced apart knuckles 37 and 38, each of which is in turn secured to a flange 39 provided on the generally cylindrical member 26 of the shoe 15. The purpose of the shaft 36 which is disposed generally parallel to the axis of the pipe section 11 will be more readily understood as the description herein proceeds.

The pipe-clamping device 10 also includes two lengths of chain generally indicated at 41 and 42 and utilized for holding the first and second sets of pipeclamping shoes l3, 14, 15 and 17, 18, 19 about the pipe sections 11 and 12 respectively. The length of chain 41 used with the pipe-clamping shoes 13, 14 and 15 is secured at one end to an eyebolt 43 having a shaft 44 formed with a right-handed thread thereon. A T- shaped coupling generally indicated at 45 includes a generally cylindrical head sleeve 46 which is pivotally supported on the aforementioned shaft 36. The coupling 45 also comprises a shaft 47 which is formed with a left-handed thread 48 thereon. The eyebolt 43 and the coupling 45 co-operate with a connector generally indicated at 50 to provide a turnbuckle adjusting mechanism which as a whole is indicated by the legend 52. The connector 50 includes two internally threaded sleeves 53 and 54 and a central hexagonal portion 55. The sleeve 53 is formed with a right-handed female thread 56 for engagement with the right-handed thread on the shaft 44 of the eyebolt 43 while the sleeve 54 is formed with a left-handed female thread 57 for engagement with the left-handed thread 48 on the shaft 47 of the coupling 45. In accordance with a particularly useful feature of this invention, the thread on the shaft 44 of the eyebolt 43 and the thread 48 on the shaft 47 of the coupling 45 are protected by sleeves or skirts 59 and 60 respectively provided on theeyebolt 43 and on the coupling 45 as will be readily understood by reference to FIGS. 5 and 6. To prevent twisting of the chain 41 secured to the eyebolt 43 when the coupling 50 is rotated, for example, using a wrench, an arm 62 extends rigidly from the skirt 59 so as to engage the outer surface of the pipe section 1 1.

The chain 41 extends around the pipe section 11 and links thereof are received within the aforementioned slots 34 in the plates 30 and 31 of the shoes 13, 14 and 15 as will be readily understood by reference to FIGS. 2, 4 and 5 of the drawings. It should perhaps be explained at this juncture, that each of the slots 34 has a width in the axial direction of the pipe section 11 which is slightly greater than the thickness of a link of the chain 41 so as to allow such a link to be inserted laterally into such aslot as indicated for the links 64 in FIGS. 4 and 5 of the drawings and so that an adjacent link 65 of the chain abuts the inner major face of a respective one of the plates 30 and 31. It can also be noted that the plates 30 and 31 usefully extend from the generally cylindrical members 25 and 26 respectively so as to be disposed generally perpendicularly to the lengths of chain extending between the pipe-clamping shoes. The pivotal mounting of the T-shaped coupling 45 on the shaft 36 permits the section of the chain 41 which is secured to the eyebolt 43 to assume a straight configuration.

It will be now understood that the pipe-clamping shoes 13, 14 and can be tightened into clamping engagement with the pipe section 11 simply by turning the connector 50 of the turnbuckle adjusting mechanism 52 in the appropriate direction. It will also be understood that the chain 41 can extend loosely around each of the shoes 13 and 14, i.e., between the plates 30 and 31 of each of those shoes, as indicated at 67 in FIG. 4 and that it is equally possible to use three separate lengths of chain instead of the single length of chain 41 herein described with reference to the accompanying drawings although such use of a single length of chain is considered to be advantageous in practice.

In accordance with another useful but optional feature of this invention, each of the plates 30 and 31 is formed with the aforementioned inturned outer edge flange 35 which serves to hinder accidental displacement of the chain from within the slots 34 as the shoes 13, 14 and 15 are being tightened into clamping engagement with the pipe section 11.

Referring further to the construction of the pipeclamping shoes 13, 14 and 15, it will be noted that the generally cylindrical members 21, 22, 24, and 26 of each of those pipe-clamping shoes are all generally of the same length while the sixth or outer generally cylindrical member 28 of each such shoe has a greater length so that it extends axially beyond the end 16 of the first pipe section 11 when the shoes 13, 14 and 15 are clamped about that pipe section in the manner already described herein. At the outer end of the generally cylindrical member 28 of each of the shoes 13, 14 and 15, there is secured thereto, for example, by welding, a threaded bolt 68 which is disposed in a generally radial direction when the pipe-clamping shoes 13, 14 and 15 are clamped in position about a pipe section such as the pipe section 1 1.

Internally threaded tubular pipe-positioning members 69 are screwed onto the bolts 68 as will be readily understood from FIGS. 2 and 3 and each of these pipepositioning members 69 is formed at its radially inner end with both a convex end surface 70 and a hexagonal peripheral configuration 71 for engagement by the jaws of a wrench. A sleeve or skirt 72 integrally formed with the generally cylindrical member 28 protects the bolt 68 of a respective one of the shoes 13, 14 and 15.

Referring further to the shoes 13, 14 and 15, it will be seen that each such shoe has mounted on the plate thereof at the left-hand end of that plate (FIG. 7) a radially outwardly extending pin 74 which is formed with an enlarged bulbous outer end 75.

The three pipe-clamping shoes 17, 18 and 19 disposed about the second pipe section 12 have many structural features in common with the pipe-clamping shoes 13, 14 and 15 already described herein. The pipe-clamping shoe 17 (FIG. 9) corresponds to the shoe 15 and is formed from five generally cylindrical members 77, 78, 79, 80 and 81 which are joined together, for example, by welding as at 82. The shoe 17 differs from the shoe 15, however, in that all five of the generally cylindrical members 77 to 81 thereof are of essentially the same length and in that a longer generally cylindrical member corresponding to the member 28 of the shoe 15 is not provided. A slotted plate 84, similar to the plate 30 of the shoe 15, is secured to the generally cylindrical member 81 while a T-shaped coupling 85 identical to the aforementioned coupling 45 is mounted on the generally cylindrical member 80. The coupling 85 forms part of a tumbuckle adjusting mechanism generally indicated at 86 and essentially identical to the turnbuckle adjusting mechanism 52. For a reason which will be more readily understood as the description herein proceeds, a radially outwardly extending pin 87 having an enlarged bulbous outer end 88 is mounted on the right-hand end of the plate 84 (FIGS. 7 and 9).

The pipe-clamping shoes 18 and 19 of the second set of shoes are identical to each other and are formed in the same way as the shoe 17 with the only difference that each such shoe is provided with two slotted plates 84 and 89 (FIG. 1) in the same manner as the plates 30 and 31 were provided on the generally cylindrical members 25 and 26 respectively of each of the pipeclamping shoes 13 and 14 of the first set of those shoes.

In accordance with another useful but optional feature of this invention, the generally cylindrical members 77 and 78 of each of the pipe-clamping shoes 17, 18 and 19 of the second set of such shoes are together provided on their radially inner surfaces with three mutually spaced apart pipe-engaging feet 91, 92 and 93 to provide a three-point mounting of each such shoe on a pipe section such as the pipe section 12.

The pipe-clamping shoes of the second set are held in position about the second pipe section 12 in proximity to the first end 20 thereof by means of the chain 42 using the turnbuckle adjusting mechanism 86 in the same manner as the shoes 13, 14 and 15 were clamped in position about the first pipe secton 11.

The pipe-clamping device 10 is completed by three axial adjustment turnbuckle mechanisms 95 (omitted from FIG. 1), one of which is shown in greater detail in FIGS. 7 and 8 of the drawings. Each of the turnbuckle mechanisms 95 comprises first and second eyebolts 98 and 99, which in turn include eyelets 101 and 102 respectively and shafts 103 and 104 respectively, the shafts 103 and 104 being formed with opposite handed threads. Each of the turnbuckle mechanisms 95 also comprises a connector generally'indicated at 105 and which in turn comprises a hexagonal central member 106 and sleeves 107 and 108 which are provided with opposite handed internal threads 109 and 110 respectively for mating engagement with the threads on respective ones of the shafts 103 and 104 of the eyebolts 98 and 99 respectively. The eyelets 101 and 102 of the eyebolts 98 and 99 respectively are dimensioned so that they can be removably and pivotally disposed about respective pairs of the pins 74 and 87 of the first and second sets of pipe-clamping shoes as shown in FIG. 7 for the shoes 13 and 18. By providing such pivotal coupling of each of the three turnbuckle mechanisms 95 to opposed pipe-clamping shoes of the two sets of such shoes, the need for exact peripheral alignment of the shoes of the two sets is avoided while the provision of the bulbous ends 75 and 88 on the pins 74 and 87 respectively reduces the chances of accidental disengagement of the turnbuckle mechanisms from those pins. In accordance with another useful but optional feature of this invention, the eyebolts 98 and 99 of each of the turnbuckle mechanisms 95 are formed with sleeves or skirts 112 and 113 respectively which protect the male threaded shafts 103 and 104 respectively of those eyebolts from damage during a pipe welding operation.

In accordance with another useful but optional feature of this invention, one of the generally cylindrical members of each of the pipe-clamping shoes of the pipe-clamping device is permanently magnetized to allow that shoe adjustably to be held in position on a respective one of the pipe sections 11 and 12 before such shoes are clamped around that pipe section, provided of course that such pipe sections are formed of a ferro-magnetic material. In the particular device shown in the accompanying drawings, the generally cylindrical members 21 of each of the pipe-clamping shoes 13, 14 and and the generally cylindrical members'77 of each of the pipe-clamping shoes l7, l8 and 19 of the second set thereof, are permanently magnetized for this purpose.

Having described the structure of the particular pipeclamping device 10 shown in the accompanying drawings, the manner in which that device is used will now be explained.

It will be assumed that the pipe sections 11 and 12 are sections of a steel pipeline, that the pipe section 11 has previously been welded to a preceeding section (not shown) of the pipeline and that it is desired to clamp the pipe section 12 in axial alignment and in correct axial spacing with the pipe section 11 so as to allow the pipe sections 11 and 12 to be welded together.

For this purpose, the pipe-clamping shoes 13, 14 and 15 of the first set thereof are first placed in angularly spaced apart positions on the outer surface of the pipe section 11 in general proximity to the first end 16 thereof, those shoes then being held in position as a result of the magnetization of the generally cylindrical members 21 of those shoes.

With the turnbuckle adjusting mechanism 52 suitably loosened, the chain 41 is then. placed around the pipe section 11 with selected links thereof laterally disposed in the slots 34 in the plates 30 and 31 of the shoes 13, 14 and 15 so that, when the connector 50 of the turnbuckle adjusting mechanism 52 is tightened, for example, by a wrench engaging the hexagonal portion 55 of that connector, those shoes will be disposed approximately equiangularly about the pipe section and tightened into clamping engagement with that pipe section, engagement of the arm 62 with the pipe section preventing twisting of the chain 41. Before and during the tightening of the turnbuckle adjusting mechanism 52, theshoes 13, 14 and 15 are carefully positioned so that the ends of the generally cylindrical members 21 and 22 of those shoes are disposed slightly inwardly from the end 16 of the pipe section 11 with the generally cylindrical members 28 of those shoes extending axially beyond that end 16 of the pipe section 11. With the pipe-clamping shoes 13, 14 and 15 so correctly positioned on the pipe section 1 1, the turnbuckle adjusting mechanism 52 is tightened to move all the shoes 13, 14 and 15 into positive clamping engagement with the pipe section 1 1.

Having clamped the shoes 13, 14 and 15 about the first pipe section 11, the pipe-positioning members 69 on the outer'ends of the generally cylindrical members 28 of the pipe-clamping shoes 13, 14 and 15 are screwed outwardly on the bolts 68 so as to allow the first end of the pipe section 12 to be moved generally into approximate axial alignment with the pipe section 11 between the pipe-positioning members 69. With the pipe section 12 temporarily supported by means (not shown), such as a crane, the pipe-positioning members 69 are then turned, for example, by means of a wrench engaging the hexagonal surfaces 71 of the pipe-positioning members 69 so as to obtain the desired precise axial alignment of the pipe sections 11 and 12. It should, however, be explained at this juncture that the pipe-positioning members 69 are not tightened to such an extent that movement of the pipe section 12 in the axial direction relative to the pipe section 11 is impossible. In circumstances where the pipe section 12 is formed of a relatively light gauge material, the pipepositioning members 69 can also be used to provide some degree of circularization to that pipe section.

The pipe-clamping shoes 17, 18 and 19 of the second set thereof are next disposed generally in their correct positions about the pipe section 12 and the chain 42 is then positioned about that pipe section and selected links of that chain 42 are inserted into the slotted plates 84 and 89 of those shoes so as to provide'certain numbers of chain links between adjacent ones of those shoes, which numbers are identical to the numbers of 7 links between opposed pairs of the shoes 13, 14 and 15 of the first set. In this way, tightening of the turnbuckle adjusting mechanism 86 on the end of the chain 42 moves the pipe-clamping shoes 17, 18 and 19 into positive clamping engagement with the pipe section 12.

Having tightened the chain 42 in the manner described to move the shoes 17 18 and 19 of the second set into positive clamping engagement with the pipe section 12, the eyelets 101 and 102 of theveyebolts 98 and 99 of each of the axial adjustment turnbuckle mechanisms are placed over respective pairs of the pins 74 and 87 as already explained and the connectors 105 of those mechanisms are then rotated, for example, by means of a wrench to move the pipe section 12 axially relative to the pipe section 11 until the axial separation required for the welding operation is obtained.

Once the welding operation has been completed, the clamping device 10 of this invention is easily removed from around the pipe sections 11 and 12 simply by unscrewing and removing the turnbuckle mechanisms 95 and then loosening the turnbuckle adjusting mechanisms 52 and 86 sufficiently to allow the chains 41 and 42 to be disengaged from the individual pipeclamping shoes. I

By providing the aforementioned skirts 59, 60, 72, 112 and 113 around the various threaded members, all risk of accidental damage to the threads of such members during a welding operation is practically completely eliminated.

Although the invention has been described with reference to the particular embodiment thereof illustrated in the accompanying drawings, it will be understood that numerous variations and modifications can be made to that particular structure without departing from the scope of the invention. Merely by way of illustration, it can be indicated that the invention is in no way restricted to the use of three pipe-clamping" device in accordance with this invention be magnetized although such magnetization is particularly useful in facilitating the initial positioning of the shoes on a pipe section. Other modifications and variations will be readily apparent to those conversant with the relevant technology.

What is claimed is:

l. A pipe-clamping device for holding adjacent first ends of a pair of pipe sections in desired mutual axial alignment and in desired axial end separation for a pipe-welding operation and which device comprises:

a first set of at least three pipe-clamping shoes;

a first set of flexible linkages for interconnecting said pipe-clamping shoes of said first set thereof;

a first tightening means associated with said first set of flexible linkages whereby, when said pipeclamping shoes of said first set thereof are disposed externally about a first one of such a pair of pipe sections in proximity to the first end of such a pipe section and in mutually angularly spaced apart positions thereabout, such flexible linkages can be tightened to move those pipeclamping shoes into clamping engagement with such a first pipe section;

at least three arms extending axially from three respective ones of said pipe clamping shoes at radially outwardly disposed positions thereon;

at least three pipe-positioning members extending generally radially inwardly from respective ones of said arms and adjustably mounted on those arms for positional adjustment in generally radial directions whereby, when said first set of pipeclamping shoes are disposed externally about the first one of the pipe sections in clamping engagement with the first pipe section, said pipe-positioning members can be radially adjusted to engage a second one of the pair of pipe sections in turn transversely to position that second one of the pair of pipe sections;

a second set of at least three pipe-clamping shoes;

a second set of flexible linkages for interconnecting said pipe-clamping shoes of said second set thereof;

a second tightening means associated with said second set of flexible linkages whereby, when said pipe-clamping shoes of said second set thereof are disposed externally about said second one of said .pair of pipe sections in proximity to said first end of said second pipe section and in mutually angularly spaced apart positions thereabout, said flexible linkages of said second set thereof can be tightened to move said pipe-clamping shoes of said second set thereof into clamping engagement with said second one of said pipe sections; and

at least three axial adjustment members extending generally axially between pairs of said pipe-clamping shoes of each of said first and second sets thereof and adapted to adjust the relative axial positions of said first and second pipe sections held in clamping engagement by said first and second sets respectively of said pipe-clamping shoes.

2. A pipe-clamping device as claimed in claim 1 in which each said pipe-clamping shoe of said first and second sets thereof comprises first and second, interconnected, generally mutually parallel and generally cylindrical members intended for disposition along a respective one of the first and second pipe sections with their axes generally parallel to the axis of that one of the first and second pipe sections.

3. A pipe-clamping device as claimed in claim 2 in which at least one of said generally cylindrical members of each said pipe-clamping shoe is permanently magnetized whereby each said pipe-clamping shoe can be detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material.

4. A pipe-clamping device as claimed in claim 2 in which said arm of each said pipe-clamping shoe of said first set thereof comprises an elongated member which is connected to and generally parallel to said first and second generally cylindrical members of a respective one of said pipe-clamping shoes of that first set thereof so as to be disposed radially outwardly and between said first and second generally cylindrical members of that shoe when that shoe is in position on a respective one of the first and second pipe sections. I

5. A pipe-clamping device as claimed in claim 4 in which said arm of each said pipe-clamping shoe of said first set thereof has secured thereto a first threaded member mating with a threaded member forming part of a respective one of said pipe-positioning members.

6. A pipe-clamping device as claimed in claim 5 in which each said pipe-clamping shoe of said first set thereof also comprises a sleeve housing a respectiveone of said first threaded members and said threaded member forming part of a respective one of said pipepositioning members.

7. A pipe-clamping device as claimed in claim 1 in which each said pipe-clamping shoe isat least in part permanently magnetized whereby it can be detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material.

8. A pipe-clamping device as claimed in claim 1 in which each said flexible linkage of said first and second sets thereof comprises a length of chain.

9. A pipe-clamping device 'as claimed in claim 1 in which each said flexible linkage of said first and second sets thereof comprises a length of chain extending between adjacent ones of said pipe-clamping shoes of a respective one of said first and second sets thereof, and in which each said length of chain is detachably connected to a respective one of said pipe-clamping shoes.

10. A pipe-clamping device as claimed in claim 6 in which each said length of chain is detachably connected to a plate which is secured to a respective one of said pipe-clamping shoes and which extends outwardly from that shoe so that, when said pipe-clamping shoes are disposed in position about respective ones of the first and second pipe sections and interconnected by said lengths of chain, each said plate is then disposed.

formed with a radially outwardly open-ended slot, each said slot being dimensioned to receive a link of a respective one of said lengths of chain laterally therein with an adjacent link of that length of chain in abutting engagement with a major face of the plate, and in which said third pipe-clamping shoe of each said set thereof is connected through a turnbuckle adjusting mechanism to one end of a respective one of said lengths of chain whereby each said set of pipe-clamping shoes can be tightened into clamping engagement with a respective one of the first and second pipe sections by adjustment of a respective one of said turnbuckle adjusting mechanisms.

12. A pipe-clamping device as claimed in claim 11 in which each said turnbuckle adjusting mechanism is pivotally connected to said third pipe-clamping shoe of a respective one of said first and second sets thereof for pivotal movement about an axis disposed generally parallel to the axis of a respective one of the pair of pipe sections when a respective one of said sets of said pipe-clamping shoes is tightened into clamping engagement with a respective one of the pipe sections.

13. A pipe-clamping device as claimed in claim 12 in which each said pipe-clamping shoe of said first and second sets thereof comprises first and second, interconnected, generally mutually parallel and generally cylindrical members intended for disposition along a respective one of the first and second pipe sections.

14. A pipe-clamping device as claimed in claim 13 in which at least one of said generally cylindrical members of each said pipe-clamping shoe is permanently magnetized whereby each said pipe-clamping shoe cane detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material.

I 15. A pipe-clamping device as claimed in claim 12 in which each said plate is formed with an inturned edge flange for engagement with a link of a respective one of said lengths of chain, which link is disposed adjacent that link of the length of chain which is disposed laterally within the slot in that particular plate.

16. A pipe-clamping device as claimed in claim 15 in which each of said first and second sets of flexible linkages comprises a single said length of chain coupled at one end thereof to a respective one of said turnbuckle adjusting mechanisms and detachably secured, at its other end as well as between its ends, to said plates secured to said pipe-clamping shoes of a respective one of said first and second sets thereof.

17. A pipe-clamping device as claimed in claim 1 in which each said pipe-positioning member is threadedly mounted on a respective one of said arms.

18. A pipe-clamping device as claimed in claim 1 in which each said axial adjustment member includes cooperating first and second threaded members operatively coupled to respective ones of said pipe-clamping shoes of said first and second sets thereof.

19. A pipe-clamping device as claimed in claim 18 in which said first and second threaded members of each said axial adjustment member are pivotally connected to respective ones of said pipe-clamping shoes of said first and second sets thereof respectively.

20. A pipe-clamping device as claimed in claim 19 in which at least one of said first and second threaded members of each said axial adjustment member is detachably connected to a respective one of said pipeclamping shoes.

21. A pipe-clamping device as claimed in claim 20 in which each said axial adjustment member includes a turnbuckle mechanism.

22. A pipe-clamping device as claimed in claim 21 in which each said axial adjustment member terminates at each end thereof in an eye loosely and removably receiving a radially extending pin provided on respective one of said pipe-clamping shoes.

23. A pipe-clamping device as claimed in claim 22 in which each said radially extending pin has an enlarged outer extremity.

24. A pipe-clamping device as claimed in claim 23 in which each said flexible linkage of said first and second sets thereof comprises a length of chain extending between adjacent ones of said pipe-clamping shoes of a respective one of said first and second sets thereof, and in which each said length of chain is detachably connected to a respective one of said generally cylindrical members of said pipe-clamping shoes.

25. A pipe-clamping device as claimed in claim 24 in which each said length of chain is detachably connected to a plate which is secured to a respective one of said pipe-clamping shoes and which extends outwardly from that shoe so that, when said pipe-clamping shoes are disposed in position about respective ones of the first and second pipe sections and interconnected by said lengths of chain, each said plate is then disposed essentially perpendicularly to the length of chain connected thereto.

26. A pipe-clamping device as claimed in claim 25 in which each of said first and second sets of pipe-clamping shoes consists of three said pipe-clamping shoes with two said plates provided on each of two said pipeclamping shoes of each said set thereof and with one said plate provided on a third said pipe-clamping shoe of each said set thereof, in which each said plate is formed with a radially outwardly open-ended slot, each said slot being dimensioned to receive a link of a respective one of said lengths of chain laterally therein with an adjacent link of that length of chain in abutting engagement with a major face of the plate, and in which said third pipe-clamping shoe of each said set thereof is connected through a turnbuckle adjusting mechanism to one end of a respective one of said lengths of chain whereby each said set of said pipeclamping shoes can be tightened into clamping engagement with a respective one of the first and second pipe sections by adjustment of a respective one of said turnbuckle adjusting mechanisms.

27. A pipe-clamping device as claimed in claim 26 in which each said turnbuckle adjusting mechanism is pivotally connected to said third pipe-clamping shoe of a respective one of said first and second sets thereof for pivotal movement about an axis disposed generally parallel to the axis of a respective one of the pair of pipe sections when a respective one of said sets of said pipe-clamping shoes is tightened into clamping engagement with a respective one of the pipe sections.

28. A pipe-clamping device as claimed in claim 27 in which each said plate is formed with an inturned edge flange for engagement with a link of a respective one of said lengths of chain, which link is disposed adjacent the link of that length of chain which is disposed laterally within the slot in that particular plate.

29. A pipe-clamping device as claimed in claim 28 in which each of said first and second sets of flexible linkages comprises a single said length of chain coupled at one end thereof to a respective one of said turnbuckle adjusting mechanisms and detachably secured, at its other end as well as between its ends, to said plates secured to said pipe-clamping shoes of a respective one of said first and second sets thereof.

30. A pipe-clamping device as claimed in claim 29 in which each said pipe-positioning member is threadedly mounted on a respective one of said arms.

31. A pipe-clamping device as claimed in claim 30 in which each said pipe-clamping shoe of said first and second sets thereof comprises first and second, interconnected, generally mutually parallel and generally cylindrical members intended for disposition along a respective one of the first and second pipe sections with their axes generally parallel to the axis of that one of the first and second pipe sections.

32. A pipe-clamping device as claimed in claim 31 in which said am of each said pipe-clamping shoe of said first set thereof comprises an elongated member which is connected to and generally parallel to said first and second generally cylindrical members of a respective one of said pipe-clamping shoes of that first set thereof so as to be disposed radially outwardly and between said first and second generally cylindrical members of that shoe when that shoe is in position on a respective one of the first and second pipe sections.

33. A pipe-clamping device as claimed in claim 32 in which said arm of each said pipe-clamping shoe of said first set thereof has secured thereto a first threaded member mating with a threaded member forming part of a respective one of said pipe-positioning members. 7

34. A pipe-clamping device as claimed in claim 33 in which each said pipe-clamping shoe of said first set 

1. A pipe-clamping device for holding adjacent first ends of a pair of pipe sections in desired mutual axial alignment and in desired axial end separation for a pipe-welding operation and which device comprises: a first set of at least three pipe-clamping shoes; a first set of flexible linkages for interconnecting said pipeclamping shoes of said first set thereof; a first tightening means associated with said first set of flexible linkages whereby, when said pipe-clamping shoes of said first set thereof are disposed externally about a first one of such a pair of pipe sections in proximity to the first end of such a pipe section and in mutually angularly spaced apart positions thereabout, such flexible linkages can be tightened to move those pipe-clamping shoes into clamping engagement with such a first pipe section; at least three arms extending axially from three respective ones of said pipe-clamping shoes at radially outwardly disposed positions thereon; at least three pipe-positioning members extending generally radially inwardly from respective ones of said arms and adjustably mounted on those arms for positional adjustment in generally radial directions whereby, when said first set of pipe-clamping shoes are disposed externally about the first one of the pipe sections in clamping engagement with the first pipe section, said pipe-positioning members can be radially adjusted to engage a second one of the pair of pipe sections in turn transversely to position that second one of the pair of pipe sections; a second set of at least three pipe-clamping shoes; a second set of flexible linkages for interconnecting said pipeclamping shoes of said second set thereof; a second tightening means associated with said second set of flexible linkages whereby, when said pipe-clamping shoes of said second set thereof are disposed externally about said second one of said pair of pipe sections in proximity to said first end of said second pipe section and in mutually angularly spaced apart positions thereabout, said flexible linkages of said second set thereof can be tightened to move said pipeclamping shoes of said second set thereof into clamping engagement with said second one of said pipe sections; and at least three axial adjustment members extending generally axially between pairs of said pipe-clamping shoes of each of said first and second sets thereof and adapted to adjust the relative axial positions of said first and second pipe sections held in clamping engagement by said first and second sets respectively of said pipe-clamping shoes.
 2. A pipe-clamping device as claimed in claim 1 in which each said pipe-clamping shoe of said first and second sets thereof comprises first and second, interconnected, generally mutually parallel and generally cylindrical members intended for disposition along a respective one of the first and second pipe sections with their axes generally parallel to the axis of that one of the first and second pipe sections.
 3. A pipe-clamping device as claimed in claim 2 in which at least one of said generally cylindrical members of each said pipe-clamping shoe is permanently magnetized whereby each said pipe-clamping shoe can be detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material.
 4. A pipe-clamping device as claimed in claim 2 in which said arm of each said pipe-clamping shoe of said first set thereof comprises an elongated member which is connected to and generally parallel to said first and second generally cylindrical members of a respective one of said pipe-clamping shoes of that first set thereof so as to be disposed radially outwardly and between said first and second generally cylindrical members of that shoe when that shoe is in position on a respective one of the first and second pipe sections.
 5. A pipe-clamping device as claimed in claim 4 in which said arm of each said pipe-clamping shoe of said first set thereof has secured thereto a first threaded member mating with a threaded member forming part of a respective one of said pipe-positioning members.
 6. A pipe-clamping device as claimed in claim 5 in which each said pipe-clamping shoe of said first set thereof also comprises a sleeve housing a respective one of said first threaded members and said threaded member forming part of a respective one of said pipe-positioning members.
 7. A pipe-clamping device as claimed in claim 1 in which each said pipe-clamping shoe is at least in part permanently magnetized whereby it can be detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material.
 8. A pipe-clamping device as claimed in claim 1 in which each said flexible linkage of said first and second sets thereof comprises a length of chain.
 9. A pipe-clamping device as claimed in claim 1 in which each said flexible linkage of said first and second sets thereof comprises a length of chain extending between adjacent ones of said pipe-clamping shoes of a respective one of said first and second sets thereof, and in which each said length of chain is detachably connected to a respective one of said pipe-clamping shoes.
 10. A pipe-clamping device as claimed in claim 6 in which each said length of chain is detachably connected to a plate which is secured to a respective one of said pipe-clamping shoes and which extends outwardly from that shoe so that, when said pipe-clamping shoes are disposed in position about respective ones of the first and second pipe sections and interconnected by said lengths of chain, each said plate is then disposed essentially perpendicularly to the length of chain connected thereto.
 11. A pipe-clamping device as claimed in claim 10 in which each of said first and second sets of pipe-clamping shoes consists of three said pipe-clamping shoes with two said plates provided on each of two said pipe-clamping shoes of each said set thereof and with one said plate provided on a third said pipe-clamping shoe of each said set thereof, in which each said plate is formed with a radially outwardly open-ended slot, each said slot being dimensioned to receive a link of a respective one of said lengths of chain laterally therein with an adjacent link of that length of chain in abutting engagement with a major face of the plate, and in which said third pipe-clamping shoe of each said set thereof is connected through a turnbuckle adjusting mechanism to one end of a respective one of said lengths of chain whereby each said set of pipe-clamping shoes can be tightened into clamping engagement with a respective one of the first and second pipe sections by adjustment of a respective one of said turnbuckle adjusting mechanisms.
 12. A pipe-clamping device as claimed in claim 11 in which each said turnbuckle adjusting mechanism is pivotally connected to said third pipe-clamping shoe of a respective one of said first and second sets thereof for pivotal movement about an axis disposed generally parallel to the axis of a respective one of the pair of pipe sections when a respective one of said sets of said pipe-clamping shoes is tightened into clamping engagement with a respective one of the pipe sections.
 13. A pipe-clamping device as claimed in claim 12 in which each said pipe-clamping shoe of said first and second sets thereof comprises first and second, interconnected, generally Mutually parallel and generally cylindrical members intended for disposition along a respective one of the first and second pipe sections.
 14. A pipe-clamping device as claimed in claim 13 in which at least one of said generally cylindrical members of each said pipe-clamping shoe is permanently magnetized whereby each said pipe-clamping shoe cane detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material.
 15. A pipe-clamping device as claimed in claim 12 in which each said plate is formed with an inturned edge flange for engagement with a link of a respective one of said lengths of chain, which link is disposed adjacent that link of the length of chain which is disposed laterally within the slot in that particular plate.
 16. A pipe-clamping device as claimed in claim 15 in which each of said first and second sets of flexible linkages comprises a single said length of chain coupled at one end thereof to a respective one of said turnbuckle adjusting mechanisms and detachably secured, at its other end as well as between its ends, to said plates secured to said pipe-clamping shoes of a respective one of said first and second sets thereof.
 17. A pipe-clamping device as claimed in claim 1 in which each said pipe-positioning member is threadedly mounted on a respective one of said arms.
 18. A pipe-clamping device as claimed in claim 1 in which each said axial adjustment member includes co-operating first and second threaded members operatively coupled to respective ones of said pipe-clamping shoes of said first and second sets thereof.
 19. A pipe-clamping device as claimed in claim 18 in which said first and second threaded members of each said axial adjustment member are pivotally connected to respective ones of said pipe-clamping shoes of said first and second sets thereof respectively.
 20. A pipe-clamping device as claimed in claim 19 in which at least one of said first and second threaded members of each said axial adjustment member is detachably connected to a respective one of said pipe-clamping shoes.
 21. A pipe-clamping device as claimed in claim 20 in which each said axial adjustment member includes a turnbuckle mechanism.
 22. A pipe-clamping device as claimed in claim 21 in which each said axial adjustment member terminates at each end thereof in an eye loosely and removably receiving a radially extending pin provided on respective one of said pipe-clamping shoes.
 23. A pipe-clamping device as claimed in claim 22 in which each said radially extending pin has an enlarged outer extremity.
 24. A pipe-clamping device as claimed in claim 23 in which each said flexible linkage of said first and second sets thereof comprises a length of chain extending between adjacent ones of said pipe-clamping shoes of a respective one of said first and second sets thereof, and in which each said length of chain is detachably connected to a respective one of said generally cylindrical members of said pipe-clamping shoes.
 25. A pipe-clamping device as claimed in claim 24 in which each said length of chain is detachably connected to a plate which is secured to a respective one of said pipe-clamping shoes and which extends outwardly from that shoe so that, when said pipe-clamping shoes are disposed in position about respective ones of the first and second pipe sections and interconnected by said lengths of chain, each said plate is then disposed essentially perpendicularly to the length of chain connected thereto.
 26. A pipe-clamping device as claimed in claim 25 in which each of said first and second sets of pipe-clamping shoes consists of three said pipe-clamping shoes with two said plates provided on each of two said pipe-clamping shoes of each said set thereof and with one said plate provided on a third said pipe-clamping shoe of each said set thereof, in which each said plate is formed with a radially outwardly open-ended slot, each said slot being dimensIoned to receive a link of a respective one of said lengths of chain laterally therein with an adjacent link of that length of chain in abutting engagement with a major face of the plate, and in which said third pipe-clamping shoe of each said set thereof is connected through a turnbuckle adjusting mechanism to one end of a respective one of said lengths of chain whereby each said set of said pipe-clamping shoes can be tightened into clamping engagement with a respective one of the first and second pipe sections by adjustment of a respective one of said turnbuckle adjusting mechanisms.
 27. A pipe-clamping device as claimed in claim 26 in which each said turnbuckle adjusting mechanism is pivotally connected to said third pipe-clamping shoe of a respective one of said first and second sets thereof for pivotal movement about an axis disposed generally parallel to the axis of a respective one of the pair of pipe sections when a respective one of said sets of said pipe-clamping shoes is tightened into clamping engagement with a respective one of the pipe sections.
 28. A pipe-clamping device as claimed in claim 27 in which each said plate is formed with an inturned edge flange for engagement with a link of a respective one of said lengths of chain, which link is disposed adjacent the link of that length of chain which is disposed laterally within the slot in that particular plate.
 29. A pipe-clamping device as claimed in claim 28 in which each of said first and second sets of flexible linkages comprises a single said length of chain coupled at one end thereof to a respective one of said turnbuckle adjusting mechanisms and detachably secured, at its other end as well as between its ends, to said plates secured to said pipe-clamping shoes of a respective one of said first and second sets thereof.
 30. A pipe-clamping device as claimed in claim 29 in which each said pipe-positioning member is threadedly mounted on a respective one of said arms.
 31. A pipe-clamping device as claimed in claim 30 in which each said pipe-clamping shoe of said first and second sets thereof comprises first and second, interconnected, generally mutually parallel and generally cylindrical members intended for disposition along a respective one of the first and second pipe sections with their axes generally parallel to the axis of that one of the first and second pipe sections.
 32. A pipe-clamping device as claimed in claim 31 in which said arm of each said pipe-clamping shoe of said first set thereof comprises an elongated member which is connected to and generally parallel to said first and second generally cylindrical members of a respective one of said pipe-clamping shoes of that first set thereof so as to be disposed radially outwardly and between said first and second generally cylindrical members of that shoe when that shoe is in position on a respective one of the first and second pipe sections.
 33. A pipe-clamping device as claimed in claim 32 in which said arm of each said pipe-clamping shoe of said first set thereof has secured thereto a first threaded member mating with a threaded member forming part of a respective one of said pipe-positioning members.
 34. A pipe-clamping device as claimed in claim 33 in which each said pipe-clamping shoe of said first set thereof also comprises a sleeve housing a respective one of said first threaded members and said threaded member forming part of a respective one of said pipe-positioning members.
 35. A pipe-clamping device as claimed in claim 34 in which at least one of said first and second generally cylindrical members of each said pipe-clamping shoe is permanently magnetized whereby each said pipe-clamping shoe can be detachably and adjustably positioned on a respective one of the first and second pipe sections when such pipe sections are formed of a ferro-magnetic material. 